The complete or partial detachment of a ligament, tendon or other soft tissue from an associated bone within the body is a relatively commonplace injury. Tissue detachment may occur as the result of an accident such as a fall, overexertion during a work-related activity, during the course of an athletic event, or in any one of many other situations or activities. Such injuries are generally the result of excess stress being placed on the tissues.
In the case of a partial detachment, commonly referred to as a “sprain”, the injury frequently heals itself, if given sufficient time and if care is taken not to expose the injury to undue stress while healing. If, however, the ligament or tendon is completely detached from its associated bone or bones, or if it is severed as the result of a traumatic injury, partial or permanent disability may result. Fortunately, a number of surgical procedures exist for re-attaching such detached tissues, as well as for completely replacing severely damaged tissues with grafts that may be formed from tissue harvested from elsewhere in the patient's body (an autograft), from another human (an allograft) or from an animal (a xenograft), or may be synthetic in origin.
A damaged anterior cruciate ligament (“ACL”) in a human knee is commonly replaced with a graft ligament by first forming bone tunnels in the tibia (“tibial tunnel”) and femur (femoral tunnel”) at nominally the points of normal attachment of the native ACL. An end of the graft ligament (which may, but not necessarily terminate in a bone block) is passed through the tibial tunnel and into the femoral tunnel, positioning the graft to span the joint space in the knee between the tunnels. The ends of the graft are then fixed in the respective tunnels. Several methods and devices for fixing the graft ligament in the femoral and tibial tunnels are known, including various types of ligament or suture anchors, buttons and staples for attaching objects to bone.
One known method for anchoring bone blocks in bone tunnels is through “cross-pinning”, in which a pin, screw or rod is inserted into the bone, transversely to the bone tunnel, so as to intersect the graft ligament (or bone block, if present), to “cross-pin” the graft in the bone tunnel. The cross-pin (i.e., the aforementioned pin, screw or rod) is generally placed in a pre-drilled passageway that is prepared using a drill guide. Methods and apparatus for effecting ACL repairs that include the use of cross-pinning drill guides are disclosed in commonly assigned U.S. Pat. Nos. 5,849,013; 6,066,173; 6,113,604; 6,379,384; 6,517,546; 6,540,783; 6,716,217; 6,958,067; 7,056,340 and 7,195,642, and U.S. patent application Ser. Nos. 10/404,685; 10/436,018; 10/436,038; 11/088,250 and 11/343,141, the contents of which are hereby incorporated by reference in their entirety.
Considerations for cross-pinning graft ligaments in the tibia differ from considerations for cross-pinning of graft ligaments in the femur. These considerations include differences in anatomical geometry, bone quality, and other considerations. These different requirements generally result in the development and application of different cross-pinning guides for femoral and tibial cross-pinning, adding complexity and expense to the performance of ACL replacement surgeries. Further, native ACLs include two functionally distinct components, the anteromedial and posterolateral bundles, and fully anatomic reconstructions of an ACL to restore the kinematics of a natural knee joint may require separate tunnels to be drilled and potentially cross-pinned for each component of the ACL, further increasing the complexity of the surgery and the requirement for multiple cross-pinning guides.
In addition, known femoral cross-pinning guides and methods for their application generally require that the femoral and tibial tunnels are substantially aligned with one another, so that a portion of the femoral guide can be passed linearly through the tibial tunnel and into the femoral tunnel for positioning femoral cross pins. This requirement for substantial alignment of the tibial and femoral tunnels does not necessarily provide optimal positioning of the replacement ligament, or ligament bundles, thereby limiting the surgeon's ability to provide fully anatomical positioning of a replacement ACL.
Accordingly, there exists a need for improved methods and apparatus for anatomical replacement of an ACL ligament in a knee.